Magnetic Fe_3O_4-Reduced Graphene Oxide Nanocomposites-Based Electrochemical Biosensing

An electrochemical biosensing platform was developed based on glucose oxidase(GOx)/Fe3O4-reduced graphene oxide(Fe3O4-RGO) nanosheets loaded on the magnetic glassy carbon electrode(MGCE).With the advantages of the magnetism, conductivity and biocompatibility of the Fe3O4-RGO nanosheets, the nanocomposites could be facilely adhered to the electrode surface by magnetically controllable assembling and beneficial to achieve the direct redox reactions and electrocatalytic behaviors of GOx immobilized into the nanocomposites. The biosensor exhibited good electrocatalytic activity, high sensitivity and stability. The current response is linear over glucose concentration ranging from 0.05 to 1.5 m M with a low detection limit of0.15 μM. Meanwhile, validation of the applicability of the biosensor was carried out by determining glucose in serum samples. The proposed protocol is simple, inexpensive and convenient, which shows great potential in biosensing application.

Photothermally Enhanced Dual Enzyme-mimic Activity of Gold-Palladium Hybrid Nanozyme for Cancer Therapy

Based on characteristics of the tumor microenvironment(TME),including acidity,hypoxia,inflammation and hydrogen peroxide overload,combined with emerging nanotechnologies,designing nanoplatforms with TME specificity/responsiveness for tumor treatment is a promising nanotherapeutic strategy.In this work,a multifunctional gold-palladium bimetallic cascade nanozyme was constructed for effective photothermal-enhanced cascade catalyzed synergistic therapy of tumors.The dumbbell-like Au-Pd bimetallic nanomaterial(Au NRs-Pd@HA)was obtained by reducing palladium on gold nanorods with ascorbic acid(AA)and further modified with hyaluronic acid(HA).The introduction of HA brings biocompatibility and targeting properties.The zebrafish embryos model showed that Au NRs-Pd@HA had good biocompatibility and low biotoxicity.Au NRs-Pd@HA can induce catalytic conversion of glucose to generate H_(2)O_(2) efficiently,and subsequently undergo cascade reaction to produce abundant·OH radicals,exhibiting peroxidase-like(POD-like)and glucose oxidase-like(GOD-like)capabilities.The generated·OH was a key factor for tumor ablation.Meanwhile,Au NRs-Pd@HA exhibits good photothermal performance under 808 nm irradiation,in favor of photothermal therapy(PTT).Especially,the POD-like and GOD-like activities were significantly enhanced due to the photothermal effect.The synergistic PTT and photothermal-enhanced nanozymes with cascade catalytic effect enabled efficient and safe cancer therapy.